In a motor vehicle, an onboard speech recognition system can be provided, for example, for voice control of vehicle components. A user can then speak a voice command, for example, which is provided to the onboard speech recognition system as voice input. The system then generates a recognition result for the voice input, which describes or indicates speech content identified in the voice input, which is to say the voice command.
However, due to limited processing resources, the recognition vocabulary of an onboard speech recognition system is restricted. Moreover, the statistical recognition model, for example a hidden Markov model (HMM), is also limited by the processing power available to the motor vehicle.
For this reason, what is known as hybrid speech recognition may be provided in a motor vehicle, in which an online speech recognition service is additionally used via a communication link. This service is likewise provided with the voice input via the communication link. The online speech recognition service can be implemented by a server of the Internet, for example. The recognition result of the speech recognition service is then provided in the motor vehicle again via the communication link. However, two recognition results are now available in the motor vehicle, these being that of the onboard speech recognition system and that of the online speech recognition service. These two recognition results are provided to a decision unit or an arbiter unit, which initially, based on a comparison, ascertains a comparison result that indicates whether the two recognition results deviate from one another. Depending on this comparison result, a decision can then be made as to whether one of the recognition results is to be used. In general, the recognition result of the online speech recognition service is more reliable, and thus to be preferred, since the online speech recognition service has more processing resources, and consequently a more extensive recognition vocabulary, as well as a more complex statistical recognition model available than the onboard speech recognition system. In this way, an incorrect recognition result of the onboard speech recognition system can be identified and suppressed when a communication link exists.
Still, it may be necessary at times to rely exclusively on the onboard speech recognition system in the motor vehicle since the communication link has been interrupted or is not available. The communication link can be formed, for example, based on a mobile communication connection and/or a wireless local area network (WLAN) connection. If such a wireless connection is presently not possible, the online speech recognition service also cannot be utilized in the motor vehicle.
Onboard speech recognition systems for voice control are known from DE 10 2009 051 508 A1 and DE 10 2008 025 532 A1, for example. So as to conduct a plausibility check of a recognition result of an onboard speech recognition system, it is known from DE 10 2005 018 174 A1 to select the result that provides the best match to entries of a database from multiple possible recognition results.
It is the object of the present disclosure to conduct a plausibility check for a recognition result of an onboard speech recognition system of a motor vehicle when it is presently not possible to check the result by way of an online speech recognition service.
The object is achieved by the subject matter of the independent claims. Advantageous embodiments of the present disclosure are described by the dependent claims, the following description, and the figures.